1. Field
The following description relates to an organic light emitting display, and more particularly, to an organic light emitting display capable of displaying an image with desired brightness.
2. Description of Related Art
Recently, various flat panel displays (FPDs) that are lighter in weight and smaller in volume than comparable cathode ray tubes (CRTs) have been developed. The types of FPDs include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and organic light emitting displays.
Among the FPDs, an organic light emitting display is capable of displaying an image using organic light emitting diodes (OLED) that generate light through the re-combination of electrons and holes. The organic light emitting display has relatively high response speed and relatively low power consumption.
The organic light emitting display includes pixels at crossing regions of data lines and scan lines, a data driver for supplying data signals to the data lines, and a scan driver for supplying scan signals to the scan lines.
The scan driver sequentially supplies the scan signals to the scan lines. The data driver supplies the data signals to the data lines in synchronization with the scan signals.
The pixels are selected when the scan signals are supplied to the scan lines to receive the data signals from the data lines. A pixel that receives a data signal charges (stores) a voltage corresponding to a difference between the voltage of the data signal and the voltage of a first power source in a storage capacitor. Then, the pixel supplies current corresponding to the voltage charged (stored) in the storage capacitor from the first power source to a second power source via the OLED to generate light with a brightness (e.g., a predetermined brightness).
However, due to the voltage drop of the first power source, a desired voltage may not be charged in the storage capacitor. Therefore, an image with desired brightness may not be displayed. In more detail, the first power source supplies a current (e.g., a predetermined current) to the OLED and a voltage drop (e.g., a predetermined voltage drop) is generated in accordance with the amount of current supplied to the OLED. In this case, the desired voltage may not be charged in the storage capacitor for charging the voltage corresponding to the difference voltage between the first power source and the data signal.
In addition, when the data signal is supplied to one terminal of the storage capacitor, the voltage of the first power source coupled to the other terminal of the storage capacitor may temporarily change. Therefore, picture quality may be further deteriorated. In particular, such a problem is severe in a high resolution and large panel where a plurality of storage capacitors are formed in units of horizontal lines (or rows).